LT1 SAE output graph
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
I think the peakiness of the curves is because the graph only shows the "top" half. If you follow the 320KW down in 10 KW increments, you end up with the Y-axis at about 100 KW, or ~134 hp. The fact that you're not seeing the whole range is stretching the curve's in the vertical direction so it appears more peaky.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
I think the peakiness of the curves is because the graph only shows the "top" half. If you follow the 320KW down in 10 KW increments, you end up with the Y-axis at about 100 KW, or ~134 hp. The fact that you're not seeing the whole range is stretching the curve's in the vertical direction so it appears more peaky.
Safety Car
Joined: Jun 2004
Posts: 4,769
Likes: 15
From: Lovin Life Oh
Im going with 495 will be your number,
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
Melting Slicks
Joined: Aug 2003
Posts: 2,245
Likes: 2,176
From: Cary NC
I took this "sae LT1" graph from the Team ZR1 website, converted it from kW to horsepower, and overlaid it with GM's same graph for the LS7.
Interestingly enough, when I do this, the "LT1" makes about the same power as the LS7 below 4000-4500rpm. This is in agreement with GM's previous claims about the low-end torque of the LT1 being a match for the LS7.
If it's not the real thing, it appears to be at least close to what we should expect.
.
Interestingly enough, when I do this, the "LT1" makes about the same power as the LS7 below 4000-4500rpm. This is in agreement with GM's previous claims about the low-end torque of the LT1 being a match for the LS7.
If it's not the real thing, it appears to be at least close to what we should expect.
.
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
Im going with 495 will be your number,
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
The LY7 (the 255 hp 3.6L) had 10.2:1 static compression, the LLT went up to 11.3:1, a nearly 11% increase.
The LS3 has a compression of 10.7:1 and the LT1 went to 11.5:1, an increase of "only" about 7%.
That alone will result in less gain from LS3 to LT1 than LY7 to LLT did. Not to mention that the LLT is DOHC making the comparison difficult anyway.
The LFX (LLT's replacement) 323hp 3.6L V6 is also at 11.5:1 static compression, so it seems like GM has settled upon that for their DI engines.
Therefore I'd expect the gains from LS3 to LT1 to be lower. If GM had wanted to limit the LT1 to premium fuel, no doubt they could have pushed for more power.
I'm expecting real close to the 465hp shown in this SAE paper graph.
Last edited by CPhelps; May 20, 2013 at 04:58 PM.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
I know you already admitted it was a terrible methodology (your words), but just some points to think about.
The LY7 (the 255 hp 3.6L) had 10.2:1 static compression, the LLT went up to 11.3:1, a nearly 11% increase.
The LS3 has a compression of 10.7:1 and the LT1 went to 11.5:1, an increase of "only" about 7%.
That alone will result in less gain from LS3 to LT1 than LY7 to LLT did. Not to mention that the LLT is DOHC making the comparison difficult anyway.
The LFX (LLT's replacement) 323hp 3.6L V6 is also at 11.5:1 static compression, so it seems like GM has settled upon that for their DI engines.
Therefore I'd expect the gains from LS3 to LT1 to be lower. If GM had wanted to limit the LT1 to premium fuel, no doubt they could have pushed for more power.
I'm expecting real close to the 465hp shown in this SAE paper graph.
The LY7 (the 255 hp 3.6L) had 10.2:1 static compression, the LLT went up to 11.3:1, a nearly 11% increase.
The LS3 has a compression of 10.7:1 and the LT1 went to 11.5:1, an increase of "only" about 7%.
That alone will result in less gain from LS3 to LT1 than LY7 to LLT did. Not to mention that the LLT is DOHC making the comparison difficult anyway.
The LFX (LLT's replacement) 323hp 3.6L V6 is also at 11.5:1 static compression, so it seems like GM has settled upon that for their DI engines.
Therefore I'd expect the gains from LS3 to LT1 to be lower. If GM had wanted to limit the LT1 to premium fuel, no doubt they could have pushed for more power.
I'm expecting real close to the 465hp shown in this SAE paper graph.
All GenV engines have DI, so GM has not settled on 11.5:1 CR across the board for it's DI engines
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Safety Car
Joined: Nov 2012
Posts: 4,737
Likes: 551
From: North California
Im going with 495 will be your number,
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
And what do you want to bet that the GenV 6.2L truck engine has a different horsepower than the GenV LT1 6.2L used in the C7.
Safety Car
Joined: Nov 2012
Posts: 4,737
Likes: 551
From: North California
Melting Slicks
Joined: Jun 2005
Posts: 2,216
Likes: 1
St. Jude Donor '12-'13-'14, '16
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
And even that's likely on the high side, 460-470hp is still a probability in my opinion.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
For instance, I can take the 5.3L GenV engine with VVT, DI and AFM and enlarge it to 6.2L, as GM did. If I extrapolate the numbers from the 5.3L version, then the LT1 should only have 415 HP, not the 450 that GM has estimated.
Both the truck and the LT1 versions have the same displacement, the same combustion design, the same compression ratio, etc, but their final configuration is based on their specific application.
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
Sorry I mean to say "no higher than" 11.5:1. Meaning even with DI, GM doesn't seem comfortable pushing higher than 11.5, so we shouldn't be expecting as large of gains as the LLT got over the LY7.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
Safety Car
Joined: Nov 2012
Posts: 4,737
Likes: 551
From: North California
My point wasn't directed directly at you, but it was that you can't just extrapolate numbers from various engines(as you pointed out) and not even when the engines are basically the same (as with the GenV engines used in the Silverado and in the C7).
For instance, I can take the 5.3L GenV engine with VVT, DI and AFM and enlarge it to 6.2L, as GM did. If I extrapolate the numbers from the 5.3L version, then the LT1 should only have 415 HP, not the 450 that GM has estimated.
Both the truck and the LT1 versions have the same displacement, the same combustion design, the same compression ratio, etc, but their final configuration is based on their specific application.
For instance, I can take the 5.3L GenV engine with VVT, DI and AFM and enlarge it to 6.2L, as GM did. If I extrapolate the numbers from the 5.3L version, then the LT1 should only have 415 HP, not the 450 that GM has estimated.
Both the truck and the LT1 versions have the same displacement, the same combustion design, the same compression ratio, etc, but their final configuration is based on their specific application.
Le Mans Master
Joined: Sep 2010
Posts: 7,579
Likes: 87
From: Chester County PA
Im going with 495 will be your number,
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
I got that with this terrible methodolgy
Caddy cts without DI is 265hp same motor with DI is 304 HP
(((304-265)/265)+1)*430
ends up right around 493 im guessing 495 because corvettes seem to like those numbers. Keeps the Z06 guys happy and who wouldnt love 495 hp. on the flip side they might do a 475hp car first year and go to 495 hp 2nd or 3rd year like they seem to do with new gens.
Pro
Joined: Oct 2007
Posts: 584
Likes: 50
From: Tampa Florida
LS7 > LT1 plus the Z weighs less, especially the earlier models. This is no rip on the C7 at all. I still suspect the car will trap 118-120.